Alright, let's solve this math problem step by step. First, we have the number 90. Next, we see the multiplication sign, which means we need to multiply something. And what are we multiplying it by? We multiply it by 237. So, we're going to take the number 90 and add it to itself 237 times.
Step 1: 0 + 90 = 90
Step 2: 90 + 90 = 180
Step 3: 180 + 90 = 270
Step 4: 270 + 90 = 360
Step 5: 360 + 90 = 450
Step 6: 450 + 90 = 540
Step 7: 540 + 90 = 630
Step 8: 630 + 90 = 720
Step 9: 720 + 90 = 810
Step 10: 810 + 90 = 900
Step 11: 900 + 90 = 990
Step 12: 990 + 90 = 1080
Step 13: 1080 + 90 = 1170
Step 14: 1170 + 90 = 1260
Step 15: 1260 + 90 = 1350
Step 16: 1350 + 90 = 1440
Step 17: 1440 + 90 = 1530
Step 18: 1530 + 90 = 1620
Step 19: 1620 + 90 = 1710
Step 20: 1710 + 90 = 1800
Step 21: 1800 + 90 = 1890
Step 22: 1890 + 90 = 1980
Step 23: 1980 + 90 = 2070
Step 24: 2070 + 90 = 2160
Step 25: 2160 + 90 = 2250
Step 26: 2250 + 90 = 2340
Step 27: 2340 + 90 = 2430
Step 28: 2430 + 90 = 2520
Step 29: 2520 + 90 = 2610
Step 30: 2610 + 90 = 2700
Step 31: 2700 + 90 = 2790
Step 32: 2790 + 90 = 2880
Step 33: 2880 + 90 = 2970
Step 34: 2970 + 90 = 3060
Step 35: 3060 + 90 = 3150
Step 36: 3150 + 90 = 3240
Step 37: 3240 + 90 = 3330
Step 38: 3330 + 90 = 3420
Step 39: 3420 + 90 = 3510
Step 40: 3510 + 90 = 3600
Step 41: 3600 + 90 = 3690
Step 42: 3690 + 90 = 3780
Step 43: 3780 + 90 = 3870
Step 44: 3870 + 90 = 3960
Step 45: 3960 + 90 = 4050
Step 46: 4050 + 90 = 4140
Step 47: 4140 + 90 = 4230
Step 48: 4230 + 90 = 4320
Step 49: 4320 + 90 = 4410
Step 50: 4410 + 90 = 4500
Step 51: 4500 + 90 = 4590
Step 52: 4590 + 90 = 4680
Step 53: 4680 + 90 = 4770
Step 54: 4770 + 90 = 4860
Step 55: 4860 + 90 = 4950
Step 56: 4950 + 90 = 5040
Step 57: 5040 + 90 = 5130
Step 58: 5130 + 90 = 5220
Step 59: 5220 + 90 = 5310
Step 60: 5310 + 90 = 5400
Step 61: 5400 + 90 = 5490
Step 62: 5490 + 90 = 5580
Step 63: 5580 + 90 = 5670
Step 64: 5670 + 90 = 5760
Step 65: 5760 + 90 = 5850
Step 66: 5850 + 90 = 5940
Step 67: 5940 + 90 = 6030
Step 68: 6030 + 90 = 6120
Step 69: 6120 + 90 = 6210
Step 70: 6210 + 90 = 6300
Step 71: 6300 + 90 = 6390
Step 72: 6390 + 90 = 6480
Step 73: 6480 + 90 = 6570
Step 74: 6570 + 90 = 6660
Step 75: 6660 + 90 = 6750
Step 76: 6750 + 90 = 6840
Step 77: 6840 + 90 = 6930
Step 78: 6930 + 90 = 7020
Step 79: 7020 + 90 = 7110
Step 80: 7110 + 90 = 7200
Step 81: 7200 + 90 = 7290
Step 82: 7290 + 90 = 7380
Step 83: 7380 + 90 = 7470
Step 84: 7470 + 90 = 7560
Step 85: 7560 + 90 = 7650
Step 86: 7650 + 90 = 7740
Step 87: 7740 + 90 = 7830
Step 88: 7830 + 90 = 7920
Step 89: 7920 + 90 = 8010
Step 90: 8010 + 90 = 8100
Step 91: 8100 + 90 = 8190
Step 92: 8190 + 90 = 8280
Step 93: 8280 + 90 = 8370
Step 94: 8370 + 90 = 8460
Step 95: 8460 + 90 = 8550
Step 96: 8550 + 90 = 8640
Step 97: 8640 + 90 = 8730
Step 98: 8730 + 90 = 8820
Step 99: 8820 + 90 = 8910
Step 100: 8910 + 90 = 9000
Step 101: 9000 + 90 = 9090
Step 102: 9090 + 90 = 9180
Step 103: 9180 + 90 = 9270
Step 104: 9270 + 90 = 9360
Step 105: 9360 + 90 = 9450
Step 106: 9450 + 90 = 9540
Step 107: 9540 + 90 = 9630
Step 108: 9630 + 90 = 9720
Step 109: 9720 + 90 = 9810
Step 110: 9810 + 90 = 9900
Step 111: 9900 + 90 = 9990
Step 112: 9990 + 90 = 10080
Step 113: 10080 + 90 = 10170
Step 114: 10170 + 90 = 10260
Step 115: 10260 + 90 = 10350
Step 116: 10350 + 90 = 10440
Step 117: 10440 + 90 = 10530
Step 118: 10530 + 90 = 10620
Step 119: 10620 + 90 = 10710
Step 120: 10710 + 90 = 10800
Step 121: 10800 + 90 = 10890
Step 122: 10890 + 90 = 10980
Step 123: 10980 + 90 = 11070
Step 124: 11070 + 90 = 11160
Step 125: 11160 + 90 = 11250
Step 126: 11250 + 90 = 11340
Step 127: 11340 + 90 = 11430
Step 128: 11430 + 90 = 11520
Step 129: 11520 + 90 = 11610
Step 130: 11610 + 90 = 11700
Step 131: 11700 + 90 = 11790
Step 132: 11790 + 90 = 11880
Step 133: 11880 + 90 = 11970
Step 134: 11970 + 90 = 12060
Step 135: 12060 + 90 = 12150
Step 136: 12150 + 90 = 12240
Step 137: 12240 + 90 = 12330
Step 138: 12330 + 90 = 12420
Step 139: 12420 + 90 = 12510
Step 140: 12510 + 90 = 12600
Step 141: 12600 + 90 = 12690
Step 142: 12690 + 90 = 12780
Step 143: 12780 + 90 = 12870
Step 144: 12870 + 90 = 12960
Step 145: 12960 + 90 = 13050
Step 146: 13050 + 90 = 13140
Step 147: 13140 + 90 = 13230
Step 148: 13230 + 90 = 13320
Step 149: 13320 + 90 = 13410
Step 150: 13410 + 90 = 13500
Step 151: 13500 + 90 = 13590
Step 152: 13590 + 90 = 13680
Step 153: 13680 + 90 = 13770
Step 154: 13770 + 90 = 13860
Step 155: 13860 + 90 = 13950
Step 156: 13950 + 90 = 14040
Step 157: 14040 + 90 = 14130
Step 158: 14130 + 90 = 14220
Step 159: 14220 + 90 = 14310
Step 160: 14310 + 90 = 14400
Step 161: 14400 + 90 = 14490
Step 162: 14490 + 90 = 14580
Step 163: 14580 + 90 = 14670
Step 164: 14670 + 90 = 14760
Step 165: 14760 + 90 = 14850
Step 166: 14850 + 90 = 14940
Step 167: 14940 + 90 = 15030
Step 168: 15030 + 90 = 15120
Step 169: 15120 + 90 = 15210
Step 170: 15210 + 90 = 15300
Step 171: 15300 + 90 = 15390
Step 172: 15390 + 90 = 15480
Step 173: 15480 + 90 = 15570
Step 174: 15570 + 90 = 15660
Step 175: 15660 + 90 = 15750
Step 176: 15750 + 90 = 15840
Step 177: 15840 + 90 = 15930
Step 178: 15930 + 90 = 16020
Step 179: 16020 + 90 = 16110
Step 180: 16110 + 90 = 16200
Step 181: 16200 + 90 = 16290
Step 182: 16290 + 90 = 16380
Step 183: 16380 + 90 = 16470
Step 184: 16470 + 90 = 16560
Step 185: 16560 + 90 = 16650
Step 186: 16650 + 90 = 16740
Step 187: 16740 + 90 = 16830
Step 188: 16830 + 90 = 16920
Step 189: 16920 + 90 = 17010
Step 190: 17010 + 90 = 17100
Step 191: 17100 + 90 = 17190
Step 192: 17190 + 90 = 17280
Step 193: 17280 + 90 = 17370
Step 194: 17370 + 90 = 17460
Step 195: 17460 + 90 = 17550
Step 196: 17550 + 90 = 17640
Step 197: 17640 + 90 = 17730
Step 198: 17730 + 90 = 17820
Step 199: 17820 + 90 = 17910
Step 200: 17910 + 90 = 18000
Step 201: 18000 + 90 = 18090
Step 202: 18090 + 90 = 18180
Step 203: 18180 + 90 = 18270
Step 204: 18270 + 90 = 18360
Step 205: 18360 + 90 = 18450
Step 206: 18450 + 90 = 18540
Step 207: 18540 + 90 = 18630
Step 208: 18630 + 90 = 18720
Step 209: 18720 + 90 = 18810
Step 210: 18810 + 90 = 18900
Step 211: 18900 + 90 = 18990
Step 212: 18990 + 90 = 19080
Step 213: 19080 + 90 = 19170
Step 214: 19170 + 90 = 19260
Step 215: 19260 + 90 = 19350
Step 216: 19350 + 90 = 19440
Step 217: 19440 + 90 = 19530
Step 218: 19530 + 90 = 19620
Step 219: 19620 + 90 = 19710
Step 220: 19710 + 90 = 19800
Step 221: 19800 + 90 = 19890
Step 222: 19890 + 90 = 19980
Step 223: 19980 + 90 = 20070
Step 224: 20070 + 90 = 20160
Step 225: 20160 + 90 = 20250
Step 226: 20250 + 90 = 20340
Step 227: 20340 + 90 = 20430
Step 228: 20430 + 90 = 20520
Step 229: 20520 + 90 = 20610
Step 230: 20610 + 90 = 20700
Step 231: 20700 + 90 = 20790
Step 232: 20790 + 90 = 20880
Step 233: 20880 + 90 = 20970
Step 234: 20970 + 90 = 21060
Step 235: 21060 + 90 = 21150
Step 236: 21150 + 90 = 21240
Step 237: 21240 + 90 = 21330

So, 90*237 = 21330